Distribution: Found throughout European and American waters. In British waters this species is most likely to be found in cold, deep areas of the seas anywhere around the British Isles.

Feeds on: Dead and rotting fish.

Description: Long, smooth, scaleless eel-eel like body which is covered in slime. Further slime producing glands run down the length of the body. What appears to be a fin runs around the tail, although this is actually a fold of skin rather than a genuine ray fin and gill openings are present rather than fish-like gills. Eyes consist of very small, basic eye holes. Mouth does not consist of hinged jaws but instead has a type of toothed disc (similar to a lamprey) which is surrounded by a number of barbules. Colours are wide-ranging and specimens can be grey, brown, orange or even pinkish.

Hagfish are certainly present around much of the British Isles, although due to their life cycle, ways of feeding and lack of commercial interest they are a species which is mostly ignored by anglers, commercial fishermen and the general public. There are over seventy different species of hagfish found worldwide, although it is only Myxine glutinosa that is found around the UK in any numbers.

Distribution

Hagfish live in deep, cold water, down to depths of 1,500 metres and possibly deeper than this. As they prefer colder waters they are more common in Scandinavian and Nordic waters in Europe, although they are also smaller populations in the Mediterranean. Research into British hagfish distribution is poor this species is likely to be found all around the British Isles where their is sufficient depth to provide suitable habitat. Populations are also present in American and Canadian waters.

Behaviour and Feeding

A hagfish emerging from its home in the seabed.

Hagfish generally live over seabeds made up of soft sediment such as sand, mud or clay as they need to be able to burrow into the seabed. Hagfish have extremely primitive eyes, which look like little more than black dots near to the snout. The eyes lack lenses and cannot focus, meaning they are only used for distinguishing between light and darkness. The hagfish therefore locate sources of food using their sense of smell which is aided by the barbules around their mouth. Although it is thought that hagfish may consume crustaceans, prawns and marine worms which are found on the seabed the main source of food is dead or rotting fish (or any other marine creature) which have fallen to the seabed. Once the hagfish has located a carcass they will feed by boring into the flesh with their disc-like, jawless mouth. If the creatures is large enough hagfish may eat their way inside of their prey, and even live inside of large creatures such as sharks and whales for a period of time. Many scientists believe that the hagfish is also capable of absorbing nutrients from other animals directly through their skin (possibly explaining why hagfish burrow their way inside animals), although this method of feeding is poorly understood. Fully grown hagfish are believed to be able to go for several months without feeding.

In areas where they are common hagfish are hated by commercial fishermen. This is due to the fact that hagfish see the fish caught in trawler’s nets, or the static nets of fixed net fisheries, as an easy meal and will enthusiastically feed on the trapped fish, ruining the catch and costing the fishermen money.

Reproduction

Very little is known about the reproductive cycle of the hagfish, although there is evidence that they are hermaphrodites, and can possibly change their sex depending on the number of males and females in an area. It is also unknown how old hagfish have to be in order to reproduce, and the maximum age they can reach is also unknown.

Slime

Hagfish have around 100 slime producing glands which are located along the length of their body. These glands are capable of producing a mucus which combines with water to create tens of litres of slime in a matter of seconds. This slime as an incredibly effective defence against predators, with even shark species being deterred from attacking hagfish by the masses of slime which clog up the attackers mouth and gills, as the pictures below show.

A BBC news feature showing the video from which the pictures above are taken can be viewed by clicking here. Hagfish are able to rid themselves of excess slime by tying their body into a knot and then squeezing through the gap which they have made.

Hagfish slime is of great interest to the scientific community due to its unique features – it is very thin but proportionately extremely strong. This BBC article reports that hagfish slime could be used as a basis to create new types of material which would replace nylon and lycra, with hagfish slime (or a man-made synthetic version based on it) being used to make high-tech breathable sportswear, bullet-proof vests and types of plastic. Although this research is still in its early stages there could be very significant human applications for hagfish slime. In summer 2017 a traffic accident in Oregon saw a truck carrying 3,000kg of hagfish crash and spill the hagfish over the road. The resultant slime produced by the hagfish meant that the road had to be closed to allow the cleanup to take place.

Commercial Value and Conservation Status

Despite their ugly looks and unpleasant way of life hagfish do have commercial value. They are commonly eaten in many Asian countries, with South Korea and Japan being notable consumers of this species. Hagfish is often kept live in tanks and killed and prepared to order for consumers with the flesh usually being prepared in stir-fry style dishes, although the skin can also be turned into a form of leather.

Left, live hagfish on sale in Busan Metropolitan City, South Korea. Right, a close up picture of hagfish live in the same tank.

While the hagfish found in British waters are ignored by commercial operations this species is commercially harvested in American waters, with almost all of the catch being exported to Asia. The IUCN (International Union for the Conservation of Nature) state that around 50 million hagfish were caught in US waters between 1991 and 1996, with over 200 million caught between 1997 and 1999, with a number of vessels fishing exclusively for this species. Hagfish were caught baited using plastic drums which were modified into ‘hagfish pots’ which allowed hagfish to swim into the drum to feed on bait but did not allow the hagfish to exit. Hagfish catches were not (and are still not) regulated, and commercial fishermen are under no obligation to declare hagfish catches. Additionally, the ICUN reports that masses of hagfish under 50cm were discarded back into the sea (where they would die) due to being classed as too small to be commercially valuable. The American hagfish fishery has declined in recent years and this species is thought to be commercially caught in much smaller quantities today than in the 1990s.

Today, hagfish are classed as a species of Least Concern by the ICUN who also state that this species is “known to be very abundant and has a large distribution.” There are also plans for regulation across much of the remaining American hagfish fishery in order to monitor stocks and provide a more accountable way of commercially catching this species.

A Prehistoric Creature, Biology and Problems with Classification

Hagfish have unusual features, with the lamprey being the only closely related species.

Hagfish are often classed as a prehistoric species due to the fact that they do not have appeared to have evolved in over 325 million years, and retain primitive features such as gill openings (rather than the gills of true fish) and rudimentary eye holes, rather than eyes with lenses which can focus. Like the closely related lamprey the hagfish defies simple classification as this species lacks paired fins and hinged jaws of fish species and has a skeleton made out of cartilage which means they are not a genuine eel species. This species is placed into the class Agnatha of jawless fish, although classification of hagfish and lamprey is often disputed and lacks a clear scientific consensus.

Interesting Fact 1: The website WhaleTimes.org created National Hagfish Day (the third Wednesday of October) to celebrate the much maligned hagfish and to draw attention to the less aesthetically pleasing (but fascinating) sea creatures which live in the world’s seas.

Interesting Fact 2: In the early 1980s a public poll was held in Norway to decide on the nation’s national fish. It was assumed that cod, haddock or herring would win, but a concerted effort (led by students who saw the funny side in disrupting the poll) saw the unappealing hagfish win by thousands of votes. The results of the poll were thrown out after a short period of time.